The Duncan plate. Relief from Copernicus GLO-30; rivers and lakes from USGS NHD; watersheds from the USGS Watershed Boundary Dataset; roads and city limits from Census TIGER 2024.
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66° on Nov. 17, 2023, the hottest reading for this week of the year since 1956. Next is 64° in 2016.
Duncan’s center stands about 1,230 ft above sea level. Within three miles the land runs from 1,200 ft to 1,430 ft, a difference of 230 ft: rolling country. The highest named summit within 15 miles is Haystack Mountain, about 1,420 ft, 3 miles south.
Under the town center the state geologic map shows Jacobsville Sandstone, from the Mesoproterozoic, 1 to 1.6 billion years old.
The section below crosses 2 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 20×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Sandstone. Age: Mesoproterozoic, 1 to 1.6 billion years old. About 15 mi of the line.
Mixed-clastic, metagraywacke. Age: Paleoproterozoic, 1.6 to 2.5 billion years old. About 9 mi of the line.
From the USGS State Geologic Map Compilation (Horton and others, 2017), the states’ geologic maps joined at a common scale.
Heights from Copernicus GLO-90 (a surface model: it includes buildings and tree canopy); summits from USGS GNIS; rivers from USGS NHDPlus HR; rock from the USGS State Geologic Map Compilation.
A raindrop that lands in Duncan reaches Lake Superior by way of Beaver Creek, the East Branch Ontonagon and the Ontonagon: about 65 river miles. From there it moves on through the Great Lakes, over Niagara Falls and down the St. Lawrence to the Atlantic.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Duncan; river miles along the main stem, rounded.
Duncan has a warm-summer humid continental climate. Summer afternoons average 77° in July; winter nights fall to about 6° in January. About 33 inches of rain fall in a normal year.
On November 14 Duncan normally reaches 40° and falls to 25°. The record high is 62°, in 1990; the record low 2°, in 1986. The most rain on this date, 0.33 in, fell in 1957.
Normals 1991–2020 and records since 1956 at Alberta Ford For Center, 18 miles east-northeast. NOAA, through RCC-ACIS.
